Abaixo está uma instrução que descreve uma tarefa de geração de SQL, combinada com uma entrada que fornece mais contexto sobre os esquemas de tabela disponíveis. Escreva o código SQL que responda adequadamente à solicitação
 ###Instrução: Qual é o código de cor com uma classificação de temperatura ordinária?
 ###Tabelas: CREATE TABLE allied_ships (allied_ships_id AUTO_INCREMENT PRIMARY KEY, Date VARCHAR, Name VARCHAR, Flag VARCHAR, Tonnage (GRT) INT, Sunk by VARCHAR) CREATE TABLE 2006_data (2006_data_id AUTO_INCREMENT PRIMARY KEY, Rank INT, Airport VARCHAR, Total Passengers INT, % Change 2005/2006 VARCHAR, International Passengers INT, Domestic Passengers INT, Transit Passengers INT, Aircraft Movements INT, Freight (Metric Tonnes) INT) CREATE TABLE operation (operation_id AUTO_INCREMENT PRIMARY KEY, Maximum Ceiling Temperature VARCHAR, Temperature Rating VARCHAR, Temperature Classification VARCHAR, Color Code (with Fusible Link) VARCHAR, Glass Bulb Color VARCHAR) CREATE TABLE scholarly_journals (scholarly_journals_id AUTO_INCREMENT PRIMARY KEY, ISSN VARCHAR, Language VARCHAR, Country VARCHAR, Frequency VARCHAR, Publication range VARCHAR, Status VARCHAR, Document Type VARCHAR) CREATE TABLE list_of_sovereign_nations_with_fewer_than_500000_people (list_of_sovereign_nations_with_fewer_than_500000_people_id AUTO_INCREMENT PRIMARY KEY, Rank INT, Country/territory/entity VARCHAR, Population INT, % of world population VARCHAR, Region VARCHAR)  
SELECT Color Code (with Fusible Link) FROM operation WHERE Temperature Classification = ordinary